Direct and indirect energy audit in arable crop production and mitigation possibilities
Direct and indirect energy use in arable farming was analyzed. Denmark and Greece were used as example cases. Based on this analysis, suggestions for mitigation of energy use are suggested. Final report is finished and submitted early 2011.
The energy analysis of Denmark revealed that ploughing ranks first amongst the direct energy costs and use of artificial fertilizers and crop protection chemicals rank high on the list of indirect energy use. Under Greek conditions, depending on the crop, irrigation and ploughing compete as direct energy costs. Similar as in Denmark, fertilizer use and chemical crop protection rank high on the list of indirect energy consumption.
Mitigation strategies for direct energy consumption include:
- Reduction of irrigation. In Denmark, this might be an option. For Greece this is no option, since there agricultural production is largely based on irrigation.
- Reduction of ploughing, by implementing no-till systems.
- Improved field management, including implementation of soil structure preserving measures such as using the correct dimensions for machinery, tires and their pressure (reduced ground pressure; RGP), controlled traffic farming (CTF).
- Yield increase, which would reduce energy consumption per unit of product.
- Changing the source of energy. The efficiency of diesel engines has not shown much improvements past decades. Hydrogen driven tractors might make a difference. Also electricity driven vehicles would be valuable option, yet the generation and long term storage of energy still is a challenge.
Mitigation strategies for indirect energy consumption include:
- Reduction of artificial fertilizer for instance by implementing organic farming
- Alternative tilling strategies would reduce indirect energy use as well, yet it might enhance the use of chemical crop protection.
It is difficult to pinpoint one recommended mitigation strategy as the actual impact of mitigation efforts depends on various conditions in each situation and thus should be adapted to these local conditions. This is indicated by the fact that the ratio of direct energy consumption to indirect energy consumption varies amongst products and cultivation practices. For Denmark, this ratio ranges between 0.3 and 6.6 for barley and clover using different cultivation practices. For Greece, this ratio ranges from approximately 0.6 for rapeseed, 1.0 for sunflower and 2.2 for sweet sorghum. Clearly, with a high ratio, mitigation options should be directed towards reducing the direct energy input. At low ratios, mitigation options can better be focussed on the indirect energy consumption.
The decision processes concerning the quest for mitigation of energy input in arable farming are closely linked to the information management system (FMIS) as the provider of data/information for these processes. In this way, the energy mitigation efforts described in this deliverable gives an example of an important management strategy, which might be integrated with the information management system of the farm of tomorrow. Further research include developing designated decision support for energy mitigation steps.
The quantitative energy analysis presented in this deliverable, was based on data that, to the best of the knowledge of the authors, reflect the current state of the art. Yet, these data do not reflect fixed laws or facts and or prone to evolution in time due to changes in cultivation practices and technology development. Besides the valuable insights studies like this produce, they also indicate the necessity for continuous research and update of the quantitative data on which they are based.